A number of medical imaging techniques have emerged for capturing still or moving pictures using dyes that can be safely introduced into living tissue. For example, fluorescent dyes may be adapted for sequestration or preferential uptake at a location of medical interest, such as a lesion. The location may then be exposed to a light source that stimulates fluorescence of the dye to permit visualization that enhances a feature of the location. Other emerging techniques employ phosphorescent, chemoluminescent, or scintillant substances to generate photons at one or more wavelengths suitable for imaging. These techniques have proven useful for medical imaging and surveillance, with applications including lesion imaging, calcium deposit imaging, and blood flow imaging.
Such imaging techniques have been enhanced with simultaneous capture and rendering of visible light images. This may, for example, provide a navigational tool at a surgical site, with the diagnostic image and the visible light image superimposed for improved visualization. Charge-coupled devices (“CCDs”) provide one well-known system for converting incident photons, or light, into a measurable electronic charge. As a significant disadvantage, current CCD systems that combine visible light and emission wavelength imaging typically employ commercially available components, and require at least two separate cameras: a first camera to capture the visible light image and a second camera for capturing the diagnostic emission wavelength which is commonly, though by no means exclusively, in the near-infrared range. A two-camera system imposes the cost of an additional camera, as well as optics for splitting the visual light wavelengths from the emission wavelength and directing each to a separate transducer. There is also additional software complexity and processing overhead in order to synchronize and superimpose image data streams from the two cameras.
There remains a need for an integrated device that captures images from visible light wavelengths and diagnostic emission wavelengths.